Muffle furnace



Oct. 8, 1929. F. 'c. GREENE ET AL I MUFFLE FURNACE 2 Shets-Sheet 1Filed. June 13, 1925 Fan/la C (imam,

0 8, 1929- F. c. GREENE EI;AL 1,730,570

MUFFLE'. FURNACE Filed June 13, 1925 2 Sheets-She et 2 5106755115: 11127016 6'. G'reamfl,

Patented Oct. 8, 1929 UNITED STATES. PATENT OFFICE.

FRANK C. GREENE, OF WAUKEGAN, AND OTTO H. HERTEL, OF CHICAGO, ILLINOISMUFFLE FURNACE Application filed June 13, 1925. Serial No. 36,787.

This invention relates to furnaces and particularly to a muffle furnacefor heating one or more retort chambers.

The furnace is adapted for heating a primary chamber through whichmaterial is continuously passed for heat treatment and it may likewisebe adapted for heating a secondary chamber, where the'material is lodgedfor a considerable time for annealing or other similar heat treatment.

The heat required by the primary chamber, of course, depends upon theprocess employed therein and the heat required may vary in difierentzones of the chamber. Likewise the heat required in the secondarychamber may vary according to the process in hand, such heat beingdifferent from that required in the primary chamber.

It is the object of the present inventionto provide a muflie furnacewherein the heat may be varied in zones to effect the required heatingof the primary chamber.

Another object of the invention is to provide means for varying the heatof the secondary chamber as required and passing the waste heattherefrom toward the primary chamber.

A further object of the invention is to provide a combustion spacehaving ports opening into a plurality of partitioned heating zones, saidports being provided with dampers to vary the port size in order. tochange the heat in the corresponding zones.

A still further object is to provide the adj acent heating zones withmovable partition sections therebetween so that adjacent zones may beopened into each other.

Another object of the .invention is to provide a furnace constructionhaving movable walls therein adjustable in combination so that thefurnace may be made an up-draft, a clown-draft, or a cross-draftfurnace, wholly, or in part, or any desired combination of these threeforms of heating.

Still other and ancillary objects and advantages arising from theparticular construction employed will be apparent from the followingdescription of an exemplary form of the invention, as disclosed in theaccom- 50 panying drawings.

in the drawings we have illustrated afurnace embodying the invention asapplied to an experimental coking oven in which coal is passedcontinuously througha tubular retort for carbonization and thence to asecond chamber-for an annealing or soaking actionunder the furtherinfluence of the heat.

Figure 1 illustrates a front elevation of the furnace with one-halfthereof shown in section along the line 1-1 of Fig. 2.

Fig. 2 shows a cross sectional view of the oven on the line 22 of Fig..1.

Because of the varied heat zones which are required to use a cokingapparatus in an experimental way, it is found desirable to provide afurnace of the type herein disclosed in which means are provided forrapidly varying the character of the operating arrangement of thefurnace while either in or out of operation. v 1 i Referring first tothe coking apparatus em ployed, there is shown atubular retort 10 inwhich a rotary screw conveyor 11 passescoal upwardly through the retort.The conveyor 11 is adapted to be driven by a stud 11 on which is mounteda gear 11 adapted to be connected to asuitable source of power (notshown). Coal is fed into the bottom of the retort by means of a secondscrew conveyor 12 located in a pipe length 13from the end of which thehelical flights of rotor 11 pick it up. The coal is supplied in crushedform to the pipe 13 either through the'feed pipe 14 or the feed pipe 15from a suitable upper supply, not shown. In the retort 10 the coal issubjected to heat to the extent desired and it is then passed as cokeover floor 16 and incline 17 into a soaking chamber 18 likewise,subjected to heat as desired.

A single furnace is employed to heat the with a water seal 19, a closedinspection opening 20, and a gas outlet 21 entering into the hydraulicmain 22.

Surrounding the retort 10 there is a furnace wall 23 of brick worksubstantially rectangular in form, the same'being supported by I-beams24. The furnace wall is spaced from the retort 10 to form an annularheating chamber 25, which surrounds the retort 10. In the furnace wall23 at vertical levels therein are fixed horizontal partition plates 26projecting into the annular space 25, there being four such plates ateach level 90 degrees apart. The plates all but touch the wall of theretort 10. The front and rear faces of the furnace are designated 27 and28 respectively. In each of the faces 27 and 28 are positionedhorizontally movable horizontal plates 29 which slide in and out of thefurnace wall alongside of the front and rear fixed plates 26. Four suchplates are shown which when fully inserted, as shown in dotted lines ofFig. 2, form an annular horizontal partition in conjunction with thefixed plates 26. Rails 30 and 31 are shown on the front and rear facesofthe furnace upon which a ladder (not shown) may be mounted to permitan operator to move plates 29 to their properposition in the furnace.

A combustion space 32 is provided adjacent the left side of the retort.l rts 33 for each horizontal zone open into the combustion space.Horizontally movable vertical dampers 34 and 35 from the front and rearwalls respectively are set into the corresponding wall openings 36 and37, a handle 39 being provided for moving or drawing each damper. .Awaste gas flue 40 is provided at the right of the retort, the coal feedpipe 14 passing therethrough. Exit ports 41 similar to the heat ports 33are provided between the flue 40 and the annular space 25. Likewise,horizontally movable vertical plates 42 and 43 are located in the frontand rear walls to close the exit ports 41. i r

The soaker 18 is surrounded or defined by brickwork 44 outside of whichare a plurality of vertical lines 45 on the four sides. The tops of thefines open into a rectangular shaped passage 46 about the chamber 18,said passage being in communication with the combustion space 32 alongthe whole length of its right hand long side which is adjacent thereto.the fines 45 to supply heat therein as desired. A plurality of spacedsecondary air ports 45 open into the fines 45 along the soaker 13.Likewise suitable fuel burning means 48 is located in the combustionchamber 32.

Adjacent the waste gas flue 40 are two heat recuperators, theseconstituting fines 49 and 50 in which a number of air carrying pipes 51are located. The recuperator fines are connected at the top with thewaste gas flue 40, and at the bottom each is connected separatelythrough pipes 52 and 53 into a flue 54 Burners 47 are placed in leadingto the stack. Dampers 55 and 56 are provided in the pipes 52 and 53. Inthe communication between the waste gas flue 40 and the recuperatorshorizontally movable vertical dampers 57 and 58 are provided. Suitableconnections (not shown) are provided for leading the preheated air frompipes 51 to the burners 47 and 48 and to the muffle furnace Space 25.

In operation of the furnace, heat is generated by burners 47 and 48, theformer heating the soaker chamber 18 and the latter supplying theremaining fuel required. The number of burners 47 which are employed isproperly adjusted to the heat required for the soaker. The total heatgenerated is passed through any or all of the ports 33 to the annularspace about the retort. The vertical dampers 34 and 35 are adjusted forthe admission of the heat or gas into the various horizontal zones. Onthe opposite side the exit ports 41 are opened to the required de greeby moving the dampers 42 and 43. The horizontal movable partition plates29 may or may not be opened as desired. With all the horizontal platesin closed position and all the vertical dampers opened, the furnace isdivided into a plurality of horizontal zones or compartments making across draft heat on the retort 10. With the upper ports 33 open, thehorizontal plates 29 drawn out, and the lower ports 41 open, theapparatus becomes a down draft furnace. With the lower ports 33 open,the horizontal plates withdrawn, and the upper ports 41 opened, thefurnace is up-draft. It is obvious that various combinations of thesemay be employed, thus giving a wide range of heat to the various zonesof the retort.

The combustion may be regulated so as to produce a greater heat in thecentral mufile furnace about the retort 10 than is produced in thecombustion chamber 32 or the flues 45. By limiting the air supplied tothe burners 47 and 48, the combustion will be incomplete and unburnedgas will pass into the hori zontal compartments about the retort. Byadmitting air into this space the combustion can be completed and theheat intensified and localized as desired, thus adding furtherflexibility to the system employed. Air supply pipes 59 and 60 areprovided for this purpose in the furnace walls with suitabledistributing means 61 inside the furnace.

The waste gas flues 49 and 50, containing the recuperator pipes 51 maybe constructed andoperated as regencrators if desired, suchcpnstruction. and operation, however, having no particular relation tothe furnace embodying the invention.

Other structures likewise may be used for other parts of the disclosedfurnace, the drawings and description of which are not to be consideredas a limitation of the invenlee tion short of the scope thereof as setforth in the appended claims.

o claim as our .invention:

1. A muflie furnace comprising, in combi-. nation, a retort to beheated, a wall associated with said retort forming a heating space,therefor, a plurality of fixed plates between said retort and said wallpartially partitioning the space therebetween into zones along theretort, movable plates adjacent said fixed plates adapted in cooperationtherewith to act as complete partitions for said zones, a heat supplyingchamber outside said wall, a waste heat chamber on the outside of saidwall opposite said heat supplying chamber, said wall having portstherein whereby the two chambers are in communication with each of saidzones, and dampers to vary the openings of said ports.

2. A muffle furnace comprising, in combination, a retort to be heated, aheating chamber surrounding said retort, a heat supplying chamberadjacent said heating chamber on one side thereof, a waste heat chamberon the other side of said heating chamber, separating walls for saidchambers having a plurality of ports therein placing said chambers incommunication, and dampers located in said ports whereby the amount anddirection of draught of heat entering and leaving the ports respectivelyto and from the heating chambermay be controlled 3. A muffle furnacecomprising, incombination, a retort to be heated, a heating chamberassociated with said retort, a heat supplying chamber adjacent saidheating chamber, a separating wall between said chambers having portstherein, partitions having movable sections in said heating chamberadapted to divide the space therein into zones extending along theretort, and movable dampers placed in said ports, said dampers and saidpartition sections being movable to control the heat to said zones andto vary the relation of adjacent zones.

4. A muffle furnace com-prising, in combination, a retort to be heated,a wall surrounding said retort forming a heating space therefor,partitions having movable sections in said space adapted to divide thespace into zones along the retort, a heat supplyingchamber outside ofsaid wall and a waste heat chamber outside of said wall opposite saidheat supplying chamber, said wall having ports therein communicatingwith said two chambers, there being one port from each zone to each ofsaid chambers, and dampers in said ports adapted to Vary the openingthereof whereby to control the heat in said zones, the movable partitionsections serving to vary the relation of adjacent zones.

5, A muffle furnace comprising, in combination, a retort to be heated, afurnace wall forming a heating space for said retort, partitioning meanshaving movable sections di- 6. A muffle furnace adapted for primary andsecondary heat treatment of material comprising, in combination, aprimary retort adapted to have material pass therethrough, a secondretort adapted to receive said material, means to heat the secondretort, furnace chambers adapted to conduct the waste heat from saidsecond retort to said first retort, auxiliary heating means forincreasing the heat impressed upon said first retort, and means todistribute the heat at the first retort in a predetermined manner, awaste heat chamber adapted to receive the waste heat from said firstretort, and pre-heating means in said waste heat chamber for thematerial entering said first retort.

7. A furnace comprising, in combination, a retort, a wall forming aheating space about said retort, a heat supplying chamber and a wasteheat chamber outside of said wall, said chambers being on opposite sidesof said retort, said-wall having a plurality of ports therein alincdalong the length of the retort for-communication with said chambers tosaid heating space, dampers for said ports, and

partitions having movable sections adapted to divide the heating spaceinto a plurality of zones alined along the length of the retort, therebeing one port to each zone from both of said chambers whereby when saidretort is vertical the furnace may be used as an up draft, down draft,cross draft, and combination draft furnace according to the position ofsaid dampers and said partition sections.

8. A furnace comprising, in combination, a vertical retort, a wallspaced therefrom to form a heating space about said retort, a heatsupplying chamber, and a waste heat chamber outside of said wall andcommunicating with said heating space, said chambers being on oppositesides of said retort, means for supplying material to the lower end ofsaid retort, additional heat supplying means extending through saidwaste heat chamber to said first mentioned means and being adapted topreheat the material before entcring the retort, means for conveying thematerial upwardly through said retort and for discharging the materialfrom the upper end of said retort,

means for heating said heat supplying cham-- ber, a second verticalretort positioned alongside said heat supplying chamber, said lastmentioned retort being adapted to receive the material discharged fromsaid first mentioned retort, a wall forming a heating space about saidlast mentioned retort, the upper end of said last mentioned heatingspace opening into the upper end of said heat supplying chamber, andmeans for heating said last mentioned heating space.

9. A furnace retort comprising, in combination, a heating chamber, aretort in said heating chamber, means for supplying heat to saidchamber, and a plurality of transverse partitions arrangedlongitudinally of saidretort and dividing the space in said heatingchamber into a plurality of zones, each partition comprising a pluralityof fixed plates spaced about said retort, and a plurality of movableplates disposed between the fixed plates and movable to open and closethe space between the latter.

10. In a furnace retort, in combination with a heating chamber and aretort insaid heating chamber, a partition in said heating chamber, saidpartition comprising a pair of laterally spaced fixed plates extendinglaterally from the wall oi. said chamber to said retort, said platesbeing arranged ninety degrees apart, and a movable plate movable alongone side of one fixed plate toward and from the other fixed plate toclose or open the space between said fixed plates, the inner ends ofsaid plates being shaped to conform to the transverse shape of saidretort.

In testimony whereof we have hereunto affixed our signatures.

FRANK C. GREENE. OTTO H. HERTEL.

